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Thankfully the final PCB has arrived back from the printers. Today I assembled the fourth and last custom PCB for the GraffitiBot project and fortunately it went together without any problems. The schematic and board layout were published in blog 4. This card uses an MCP23008 I/O expander with I2C interface to drive 8 FETs that control the pumps. I had to use this chip because I ran out of microcontroller pins to control all the pumps. The field effect transistors have a very low gate thres ...
1.     Aims 2.     Tests 3.     My Code 4.    Solder Those SBs 5.     Next Steps in Blog#7   1.     Aims Quite simply to get some of the data that I can see on a USB terminal from the SensorTile and read it via UART or something else by the STM32F411RE Nucleo board; as this is where the main 'brains' of R2B4 will be running.   This is a very quick upd ...
This is the big milestone tenth blog in this design challenge, but there is still a lot of work to do with only 4 weeks left. My LCD PCB finally came back from the being printed, so I can connect up the liquid crystal displays and start programming. The schematic design and PCB layout were covered in blog 5. Here is what the bare card looks like: It is red because that was the lowest cost color at the time of ordering. Here is what it looks like assembled with connectors for 2 LCDs, 3 sens ...
14rhb

R2B4 #5 - L298 Troubles

Posted by 14rhb Feb 24, 2019
1.     Background 2.     Circuit Requirements 3.     An Easier Solution? 4.     Drivebelts 5.    Conclusions of #5 6.     What Next 1.     Background I had planned on driving the NEMA-17 stepper motors from my Sealed Lead Acid (SLA) 12v battery via a pair of L298 modules; these seemed to be idea from the specifications but fellow Element1 ...
1.     The Wheels 2.     The Axles 3.     The Bearings 4.     Basic Chassis 5.     Drive System and Pulley 6.     Motor Test with L298 Module (and Ardunino Uno ) 7.     Next Steps for blog #5 Welcome to blog #4 on R2B4 which brings together all the bits I've been thinking about and calculating into a series of photos showing the ...
This blog describes assembly and testing of the TE Connectivity magnetic angle sensor. The circuit design was described in a previous blog. The PCB arrived a couple of weeks ago, but I had to wait for parts to build it. I had ordered parts from Newark using a shopping cart I won in a Project14 contest. They came in this week accompanied by an $18 shipping charge but I am now able to assemble these cards. Here is what it looks like. Note the sensor chip is on the underside of the card to allo ...
I finally received enough parts to assemble the load cell signal conditioning circuit board. The circuit schematic and PCB layout for load cell signal conditioning were covered in a previous blog. The TE Connectivity FX1901 load cell will be used to measure the amount of fluid in the Graffitibot reservoir by weighing it. It isn't clear which variant of load cell (in terms of full scale output) I have, so I will have to hook it up and see what the output looks like. Also I am not quite sure h ...
  1.     Overview 2.     Motor Traction 2.1     Calculation of Motor Traction 2.2     Traction Summary 3.     Speed Calculations 4.     Hardware 5.     Drive Path 6.     Making Wheels 7.     What Next 1.     Overview I plan on using NEMA17 stepper motors ...
1.     Background 2.     The Provided Kit 3.     My Software Development Choices 4.     Sensor Tile Software 5.     Combining the Nucleo and SensorTile Cradle - What Did I Get ? 6.     Additional Hardware/Software Required 7.     Next Steps 1.     Background This blog post follows on from R2B4 - #1 An Introduc ...
Two of the PCBs I designed for the GraffitiBot came in but I won't have enough components to assemble them until at least next week. Here is what they look like: One interfaces to the load cell and one interfaces to the magnetic angle sensor.   While waiting for parts I have started looking at the software. ST Microelectronics has written a lot of software for this sensor tile and I am including some of the links in this blog. There are multiple links on each of the pages I have linked. ...
Greetings from the UAV R&D group. We hope all our fellow competitors are having a good time with the designing. Last month has been quite fulfilling for us as a research group. We were able to overcome some hurdles and complete the assembly of the drone. Also, there has been some progress in the sensor department. This post is all about it and also as you read through it, if some suggestion or doubt pops up in your head, feel free to comment.   The team has been working on identifying n ...